Drafting machine

ABSTRACT

A track-type drafting machine wherein the tracks are tubular enclosures each comprising channel-shaped members disposed in open face to face relation with one flange of each member interfitting with the corresponding flange of the other member and with the other flange of each member disposed in spaced relation to define a slot therebetween them which elements of the carriages extend.

0 United States Patent 1151 3 673 691 9 9 Gilbert 1 July 4, 1972 s41 DRAFTING MACHINE 3,153,284 l0/1964 Harris ..33/79 3,296,70! l/l967 Wolf ..33/77 [72] k'f z gg' 3,354,550 ll/l967 Lcschinger et al ..33/79 [73] Assignee: Ray And Gilbert Proprietary Limited, Vic- FOREIGN PATENTS OR APPLICATIONS wria, Australia 550,141 l0/l956 Italy ..33 79 [221 Ffled: 1969 Primary ExaminerHarry N. Haroian [21] Appl. No.: -884,245 AlwrneyWenderoth, Lind & Ponack 57 ABSTRA [52] U.S.Cl ..33/76 I 1 CT [51] Int, Cl A track-type drafting machine wherein the tracks are tubular 58 Field of Search ..33/76, 79, so enclosures each comprising channel-Shaped members 1 disposed in open face to face relation with one flange of each 56] References Cited member interfitting with the corresponding flange of the other member and with the other flange of each member disposed in UNITED STATES PATENTS spaced relation to define a slot therebetween them which ele- 1,149,120 8/1915 Fortune ..33/26 memsofthe camages mend 3,047,954 8/1962 l-lislop ..33/76 5 Claims, 4 Drawing Figures I 1 ll 11 J & *7'35 a i 27 it 7 q /9 W11:

P'A'TEMTEIJJIJL 4 I972 SHEET 1 BF 2 FIG.|.

LESLIE ARTHUR GILBERT, Inventor I ldwhtw wd/ 21 0M Attorneys P'A'TENTEDJULW 1972 3. 673.691

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Iv L 34 LESLIE ARTHUR GILBERT, Inventor ZUMd/EQZMW Attorneys DRAFTING MACHINE This invention relates to track-type drafting machines having a first travelling carriage guided by a horizontally disposed first rail and a second rail suspended from said first carriage normal to the first, rail and utilized to support and guide a second travelling carriage supporting a drawing head.

It is the principal object of the present invention to provide an improved drafting machine which is of compact, economic construction, having all precision parts accurate and stable in operation, and enclosed to protect them from accidental damage, dust and other possible destructive effects.

It is a further object of the present invention to provide a drafting machine of economic construction which is highly precise and stable in operation.

There is thus provided according to the present invention a drafting machine comprising a first track disposed horizontally and located in a first tubular enclosure having a slot extending the length of the first track, a first carriage supported on said first track for movement therealong and having a portion extending outward through the slot, said first carriage supporting a second track extending normal to said first track and located in a second tubular enclosure having a slot extending the length of said second track, and a second carriage supported on said second track 'for movement therealong and having a portion extending outwardly through said slot to support a drawing head.

Preferably, said second tubular enclosure also houses means to counter balance said second carriage and drawing head for ease of movement along the second track.

Conveniently the first and second tubular enclosures each comprise two channel-shaped members with one flange of each member interfitting with each other and the other flange of each member defining therebetween the slot. The first and second tracks are each formed by a V-shaped groove on the innerface of each flange of one channel-shaped member.

original extruded form without any subsequent machining. The grooves 23 are not used inthe horizontal tubular member 10, but are used to support the counter-balance 24, in the second tubular member 13.

Although the interfitting tongue and groove 18 and 19 serve to connect extrusions l6 and 17, a suitable adhesive is applied to the interengaging faces to provide a permanent and secured joint between the two extrusions forming the tubular member.

The V-shaped grooves 22 in the horizontal tubular member 10 constitute a track for the rollers 27, mounted on the carriage 12. The peripheral edge of each roller is also of V- shaped section so as to co-operate with the V-shaped grooves in the manner preventing both lateral and vertical movement between the carriage l2 and the tubular member 10. Preferably two or more of the rollers 27 are adjustably mounted on the carriage 12 so that manufacturing tolerances can be compensated for when assembling the carriage to the tubular member.

The tubular member 13 has secured to the upper-end thereof the mounting plate which is pivotally connected to the carrier 12 by bearing pins 31.

The carrier 14 is supported within the vertical tubular member 13 in the same manner as previously described with respect to carriage 12, but the portion of the carriage extending laterally through the slot 20 is adapted to receive a conventional drawing head in the conventional manner.

As the second tubular member is normally operated with the V-shaped grooves 22 in a vertical or substantially vertical disposition it is necessary to provide a counter-weight for the carriage l4 and the attached drawing head. This counterweight 24 carries a plurality of rollers 25 having a V-shaped periphery which engage within the V-shaped grooves 23. Adjacent and within the upper and lower end of the tubular member 13, are mounted guide pulleys 34 joumalled on spindies 35 within the tubular member. Respective inextensible This construction provides enclosed tracks and carriages protected from dust and damage. The machine thus operates smoothly, wear is reducedand adjustment unnecessary.

The invention will be more readily understood from the following description of one practical arrangement of the drafting machine as illustrated in the accompanying drawings.

In the drawings,

- FIG. 1, is a plan view of the drafting machine,

FIG. 2, is a vertical section through the drafting machine.

FIG. 3, is a cross section of the second track and tubular enclosure.

FIG. 4, is an enlarged sectional view of one carriage showing the locking device.

Referring now to the drawings, the drafting machine comprises the tubular member 10 of rectangular cross section which may be secured in a horizontal disposition to the upper portion of the drawing board 1 l. The carriage 12, is supported within the tubular member 10 and has suspended from a portion thereof the second tubular member 13 disposed normal to the tubular member 10. The second carriage 14 is supported in the second tubular member and is adapted to receive a conventional drawing head 15, shown in broken outline in FIG. 1.

Tubular members 10 and 13 are the same basic construction which can best be seen from the cross section of tubular member 13 shown in FIG. 3. The box-shaped tubular member is made up from two channel-shaped metal extrusions l6 and 17 with the tongue 18 on the extrusion l7 interfitting with the groove 19 of the extrusion 16. The tongue 18 and groove 17 are respectively formed in one flange of each extrusion so that when the tongue and groove are assembled together, the other flanges 17a and 16a, define the slot 20 extending longitudinally along the full length of the tubular member.

On the innerface of the flanges of the extrusion 16, are formed V-shaped tracks 22, which are initially formed during extrusion, and are subsequently machined to the finished shape before the extrusions l6 and 17 are assembled together.

V-shaped grooves 23 are also formed on the innerface of each flange of the extrusion 17, but these grooves are in the flexible elements 38 pass about the guide pulleys and are secured atone end of the carriage l4 and at the other end to the counter-weight 24. The flexible elements are maintained under tension by suitably disposed springs. Thus movement of the carriage along the grooves 22 effects an equal and opposite movement of the counter-weight along the grooves 23.

Each carriage 12 and 14 carry a brake mechanism whereby the carriage may be locked at any desired location along the respective tracks. The locking mechanism comprises a member 40 secured to the carriage by the screw 41, and having at a location spaced from the screw 41, a friction pad 43, and an inclined surface 44. The lock lever 45 is pivoted to the carriage at 46, and carries a wedge block 47 slidably within the groove 48 in the carriage. Movement of the wedge block along the inclined face 46 causes deflection of the member 40 so as to bring the friction pad 43 into engagement with the innerface of the web of the tubular member. The friction force so created is sufficient to prevent free movement of the carriage along the track.

The lower end of the tubular member 13, has a cross-bar 50 fitted thereto supporting a pair of rollers 51, which support the lower end of the tubular member on the drawing board 11 when the drafting machine is within use.

As the tracks and rollers supporting the respective carriages are enclosed they are protected against accidental damage and from the collection of dust thereon. Also as the tracks are formed as an integral part of an extruded metal section the likelihood of distortion is reduced without unnecessarily increasing the bulk of the track and enclosure.

I claim:

1. A drafting machine comprising a first track disposed horizontally and located in a first tubular enclosure having a Slot extending the length of the first track, a first carriage supported on said first track for movement therealong and having a portion substantially parallel to the plane of said first track extending outward through the slot, said first carriage supporting a second track extending normal to said first track and located in a second tubular enclosure having a slot extending the length of said second track, and a second carriage supported on said second track for movement therealong and having ,a portion substantially parallel to the plane of said second track and extending outwardly through said slot to support a drawing head, and wherein the first and second tubular enclosures each comprise two channel-shaped members disposed in open'face to face relation with one flange of each member interfitting with the corresponding flange of the other member and with the other flange of each member disposed in spaced apart relation to define the slot therebetween.

2. A drafiing machine as defined in claim 1 wherein said first and second tracks are each formed by a pair of opposed V-shaped grooves constituted by a V-shaped groove on the innerface of each flange of one channel-shaped member.

3. A drafting machine as defined in claim 2 wherein said first and second carriages each include two pair of rollers, one

pair seating in rolling engagement in each V-shaped groove in the respective tubular enclosures.

4. A drafting machine as defined in claim 2 wherein a counter-weight is located in saidsecond enclosure and supported on rollers in seating engagement respectively with a similar groove formed in the innerface of each flange of the other channel-shaped member forming the second enclosure, and said counter-weight being operatively connected to said second carriage to balance the weight of the second carriage.

5. A drafting machine as defined in claim 4 wherein a guide pulley is mounted in said second enclosure adjacent each end and respective flexible members pass around each pulley to be secured to said second carriage and counter-weight, respectively.

l I I I I 

1. A drafting machine comprising a first track disposed horizontally and located in a first tubular enclosure having a slot extending the length of the first track, a first carriage supported on said first track for movement therealong and having a portion substantially parallel to the plane of said first track extending outward through the slot, said first carriage supporting a second track extending normal to said first track and located in a second tubular enclosure having a slot extending the length of said second track, and a second carriage supported on said second track for movement therealong and having a portion substantially parallel to the plane of said second track and extending outwardly through said slot to support a drawing head, and wherein the first and second tubular enclosures each comprise two channel-shaped members disposed in open face to face relation with one flange of each member interfitting with the corresponding flange of the other member and with the other flange of each member disposed in spaced apart relation to define the slot therebetween.
 2. A drafting machine as defined in claim 1 wherein said first and second tracks are each formed by a pair of opposed V-shaped grooves constituted by a V-shaped groove on the innerface of each flange of one channel-shaped member.
 3. A drafting machine as defined in claim 2 wherein said first and second carriages each include two pair of rollers, one pair seating in rolling engagement in each V-shaped groove in the respective tubular enclosures.
 4. A drafting machine as defined in claim 2 wherein a counter-weight is located in said second enclosure and supported on rollers in seating engagement respectively with a similar groove formed in the innerface of each flange of the other channel-shaped member forming the second enclosure, and said counter-weight being operatively connected to said second carriage to balance the weight of the second carriage.
 5. A drafting machine as defined in claim 4 wherein a guide pulley is mounted in said second enclosure adjacent each end and respective flexible members pass around each pulley to be secured to said second carriage and counter-weight, respectively. 